1. Field of the Invention
The present invention relates to a lens device of a television camera, and particularly relates to a lens device of a television camera including a flange-back adjusting mechanism for moving a master lens forward and backward in an optical axis direction.
2. Description of the Related Art
Conventionally, among lens barrels for television cameras for commercial use, broadcast stations, and so on, lens barrels including both of a hanging mount (also referred to as a hanger mount) for mounting a large camera and a bayonet mount for mounting a portable camera have been known.
When a television camera cannot be mounted on a hanging mount or a bayonet mount (for example, a camera manufactured by a different manufacturer from that of a lens barrel), the television camera can be combined for use with the lens barrel by using a lens supporter for mounting a television camera (also referred to as a built-up unit), the lens supporter being mounted on the hanging mount (Japanese Patent No. 3443919). FIG. 1 shows an example in which a television camera K is mounted on a lens supporter S mounted on a hanging mount 11.
When the lens supporter S is mounted on a lens barrel 10, a flange surface 12a of a bayonet mount 12 may interfere with the television camera K, depending upon the position of the television camera K mounted on the lens supporter S. Thus in order to prevent the interference, as shown in FIG. 1, the television camera K is mounted on the lens supporter S slightly away from the flange surface 12a of the bayonet mount 12. When the television camera K is mounted thus slightly away from the flange surface 12a of the bayonet mount 12, the imaging surface of the television camera K and an image-forming position are “displaced” from each other. The “displacement” can be corrected to some extent by a flange-back adjusting mechanism provided in the lens barrel and so on.